Ribbon conductors are finding an ever broader field of application in many fields of technological use, because, with them, it is possible to construct, in a simple way, preformed wiring sets that can be installed simply and rapidly during assembly. One field of application of these ribbon conductors is increasingly the motor vehicle industry, because, owing to the use of many electronic components in vehicles, the resulting flows of current are becoming increasingly large. The larger conductor cross section required for a larger current flow can be accommodated in the case of ribbon conductors by the width of the conductive track.
When two ribbon conductors are connected, among other things, spring elements are used, which are arranged in such a way that they afford the normal contact force between the two ribbon conductors required for the contact.
Known from FR A 1,236,251 is a plug connector for connecting two ribbon conductors, wherein each ribbon conductor is held in place in a respective holder, which has a spring element by means of which the ribbon conductor is clamped. In this plug connector, however, each of the ribbon conductors stripped of insulation lies on its respective holder with its contact surface exposed.
Known from DE 198 32 011 A1 is a junction region for connecting two ribbon conductors, in which one of the ribbon conductors is arranged in the interior of the housing of this junction region around a holder that can be shifted in the housing. This holder has spring elements that press one ribbon conductor against the other ribbon conductor in order to produce the requisite normal contact force. This junction region is complicated and costly in terms of its overall construction with its shiftable holder, because an adjusting mechanism that can pivot and produces the requisite normal contact force is provided.
Of crucial importance for good electrical contact is the contact resistance between the two ribbon conductors at the contacting site as well as the normal contact force exerted at this contacting site. Depicted in FIGS. 1 and 2 are the curves of measurements, carried out by the applicant, that are concerned with these crucial decision-making parameters.
Plotted in FIG. 1 is the contact resistance between two conductive tracks as a function of the normal contact force applied for a flexible ribbon conductor with a thickness of 200 μm. As is evident from this figure, the contact resistance is constant starting from a normal contact force of approximately 2 N and does not become any smaller. It can be concluded from this that a normal contact force of ≧2 N minimizes the contact resistance between two conductive tracks. Plotted in FIG. 2 is the plastic deformation of conductive tracks of 100 μm and 200 μm thickness that results when a test ball with a diameter of 2 mm is pressed with a certain test force on the stripped bare copper conductive track. As is evident from the two measurement curves represented, there results a detectable plastic deformation for a ball diameter of 2 mm only above a force of approximately 2 N at a conductor thickness of 100 μm and only above a force of 4 N at a conductor thickness of 200 μm. It can be concluded from the measurement curves shown in FIGS. 1 and 2 that the connection of two ribbon conductors is readily possible given a proper placement of the contact sites and that the normal contact force should lie at approximately 2 to 4 N depending on the thickness of the conductive tracks.